Human Resource UseHuman Values & Attitudes (Socio-political)
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Transcript of Human Resource UseHuman Values & Attitudes (Socio-political)
Human Resource Use Human Values & Attitudes (Socio-political)
Human Land Use Practices 1) Agriculture2) Suburban Development
Let’s pick on Indiana:
• 97% of land in state = privately-owned
• In central Indiana, • 70+% of land in row crop• <10% in forest• Urban sprawl intensifying
Human Impacts Ecosystem simplification: elimination of
species from food webs via human alterations to land
Example: vertebrate communities in ag. landscapes
Intensive Agriculture&
Clean Farming
Timber Extraction&
Fragmentation
Formation of Terrestrial “Islands”
Oceanic Island = Terrestrial Island ?????
Species-Area Relationship
S = cAz
S = # of species
A = island area
• Positive correlation between island size & number of species
• Applies to terrestrial “islands” also
Island Biogeography
• equilibrium model suggesting that the number of species occurring on an island represents a balance between immigration (in) and extinction (out)
• Robert MacArthur & E.O. Wilson
Habitat Fragmentation • Process of breaking contiguous unit into
smaller pieces; area & distance components
• Leads to:
< remnant patch size
> edge:interior ratios
> patch isolation
< connectivity• Community & Ecosystem processes
altered
Formation of Terrestrial “Islands”
#patches
Patch isolation
Patch size
Edge
What about aquatic systems?
What about aquatic systems?Con.Bio 12(6)
Increased Edge Habitat
Increased Edge Habitat
Habitat Fragmentation • First-Order Effects: fragmentation leads
to change in a species’ abundance and/or distribution
• Higher-Order Effects: fragmentation indirectly leads to change in a species abundance and/or distribution via altered species interactions
Habitat Fragmentation • area-sensitive species: species that
require minimum patch size for daily life requirements
• Edge effects: influence of factors from outside of a patch
Edge Effects • Habitat surrounding a patch can:
- change abiotic conditions; e.g., temp.
- change biotic interactions, e.g., predation
Example of nest predation = edge effect of approximately 50 m into forest patch
But can extend 100’s of meters….maybe km’s
Edge Effects
• How does patch size (in a landscape) & shape affect amount of edge?
• Groups – give me a mathematical example with forested landscapes that have timber extraction via clearcutting
rNdt
dN
K
NrN
dt
dN1
Exponential vs. Logistic
No DDAll populations same
DDAll populations same
No Spatial component
Incorporating Space
Metapopulation: a population of subpopulations linked by dispersal of organisms
• subpopulations separated by unsuitable habitat
• subpopulations differ in population size & distance between
Metapopulation Model
eppcpdt
dp 1
p = habitat patch (subpopulation)c = colonizatione = extinction
Another Population Model
Source-sink Dynamics: grouping of multiple subpopulations, some are sinks & some are sources
Source Population = births > deaths = net exporter
Sink Population = births < deaths
<1
<1
>1
Source-sink Dynamics
Source-sink Dynamics
Corridors
Who Cares?
Why bother discussing these models?
Metapopulations & Source-sink Populatons highlight the importance of:
• habitat & landscape fragmentation
• connectivity between isolated populations
• genetic diversity
Vancouver Island marmot(Marmota vancouverensis)
Isolated from hoary and Olympic marmots
~100 left
Vancouver Island marmot(Marmota vancouverensis)
Natural tree succession
Vancouver Island marmot(Marmota vancouverensis)
• Logging – disjunct patches- max. dispersal = 7 km
• Climate• Prey-Predator Dynamics
Differential Sensitivities to Habitat Alteration
• Niche breadth (diet & habitat) – inverse relation
• Range periphery = more sensitive (W & N)
• Body size = mobility (allometric relation)
• Social and territorial behavior (limited K)
Swihart et al. 2003
Ways to Manage
1) Featured Species Mgt
– single species
– particular purpose
– e.g., white-tailed deer
– could also include “umbrella species” and “flagship species” or “sensitive species”
Ways to Manage2) Species Richness Mgt
– maintain diversity and certain # of each species (follow MVP concept)
3) Indicator Species Mgt
– use a species (or group of species) to monitor environmental conditions
– not necessarily managing for these spp.
– bioindicators, biosentinels, “canary in coal mine”
Ways to Manage
4) Guild Mgt or Life-Form Mgt
– grouping of species based on use of same type of resources (e.g., foraging guilds)